The present invention relates to a composition comprising at least one biological control agent selected from specific microorganisms and/or a mutant of these strains having all the identifying characteristics of the respective strain, and/or a metabolite produced by the respective strain that exhibits activity against insects, mites, nematodes and/or phytopathogens and at least one fungicide (I) in a synergistically effective amount. Furthermore, the present invention relates to the use of this composition as well as a method for reducing overall damage of plants and plant parts.
Synthetic insecticides or fungicides often are non-specific and therefore can act on organisms other than the target ones, including other naturally occurring beneficial organisms. Because of their chemical nature, they may be also toxic and non-biodegradable. Consumers worldwide are increasingly conscious of the potential environmental and health problems associated with the residuals of chemicals, particularly in food products. This has resulted in growing consumer pressure to reduce the use or at least the quantity of chemical (i.e., synthetic) pesticides. Thus, there is a need to manage food chain requirements while still allowing effective pest control.
A further problem arising with the use of synthetic insecticides or fungicides is that the repeated and exclusive application of an insecticide or fungicides often leads to selection of resistant microorganisms. Normally, such strains are also cross-resistant against other active ingredients having the same mode of action. An effective control of the pathogens with said active compounds is then not possible any longer. However, active ingredients having new mechanisms of action are difficult and expensive to develop.
The risk of resistance development in pathogen populations as well as environmental and human health concerns have fostered interest in identifying alternatives to synthetic insecticides and fungicides for managing plant diseases. The use of biological control agents (BCAs) is one alternative. However, the effectiveness of most BCAs is not at the same level as for conventional insecticides and fungicides, especially in case of severe infection pressure. Consequently, known biological control agents, their mutants and metabolites produced by them are, in particular in low application rates, not entirely satisfactory.
Thus, there is a constant need for developing new, alternative plant protection agents which in some areas at least help to fulfill the above-mentioned requirements.
Example 13 of WO 98/50422 discloses a synergistic effect of a mixture comprising Bacillus subtilis AQ713 (NRRL Accession No. B-21661) and azoxystrobin. However, due to the nature of synergism it is not possible to predict the effect of other biological control agents in combination with other fungicide based on this specific example.
In view of this, it was in particular an object of the present invention to provide compositions which exhibit activity against insects, mites, nematodes and/or phytopathogens. Moreover, it was a further particular object of the present invention, to reduce the application rates and broaden the activity spectrum of the biological control agents and fungicides, and thereby to provide a composition which, preferably at a reduced total amount of active compounds applied, has improved activity against insects, mites, nematodes and/or phytopathogens. In particular, it was a further object of the present invention to provide a composition which, when applied to a crop, results in a decreased amount of residues in the crop, thereby reducing the risk of resistance formation and nevertheless provides efficient disease control.
Accordingly, it was found that these objects at least partly are solved by the compositions according to the invention as defined in the following. The composition according to the present invention preferably fulfills the above-described needs. It has been surprisingly discovered that the application of the composition according to the present invention in a simultaneous or sequential way to plants, plant parts, harvested fruits, vegetables and/or plant's locus of growth preferably allows better control of insects, mites, nematodes and/or phytopathogens than it is possible with the strains, their mutants and/or their metabolites produced by the strains on the one hand and with the individual fungicides on the other hand, alone (synergistic mixtures). By applying the biological control agent and the specified fungicide according to the invention the activity against insects, mites, nematodes and/or phytopathogens is preferably increased in a superadditive manner. Preferably, the application of the composition according to the invention induces an increase in the activity of phytopathogens in a superadditive manner.
As a consequence, the composition according to the present invention preferably allows a reduced total amount of active compounds to be used and thus the crops which have been treated by this composition preferably show a decreased amount of residues in the crop. Accordingly, the risk of resistance formation of harmful microorganisms is decreased.